JEE Mains JEE Advance BITSAT
JEE Mains | PYQ

Year

All years 2026 2025 2024 2023 2022 2021

The standard reduction potential values of some of the p-block ions are given below. Predict the one with the strongest oxidising capacity.

Standard electrode potentials for a few half cells are mentioned below:
$ E^\circ_{\mathrm{Cu^{2+}/Cu}} = 0.34 \, \mathrm{V}, \; E^\circ_{\mathrm{Zn^{2+}/Zn}} = -0.76 \, \mathrm{V} $
$ E^\circ_{\mathrm{Ag^{+}/Ag}} = 0.80 \, \mathrm{V}, \; E^\circ_{\mathrm{Mg^{2+}/Mg}} = -2.37 \, \mathrm{V} $
Which one of the following cells gives the most negative value of $ \Delta G^\circ $?

The major product of the following reaction is: $ \mathrm{CH_3CH_2CH{=}O} \xrightarrow[\text{reflux}]{\text{excess } \mathrm{HCHO}\ \text{alkali}} \ ? $

$ 0.2\% \, (\text{w/v}) $ solution of $ \text{NaOH} $ is measured to have resistivity $ 870.0 \, \text{m}\,\Omega\,\text{m} $. The molar conductivity of the solution will be __________ $ \times 10^{2} \, \text{mS dm}^{2} \, \text{mol}^{-1} $. (Nearest integer)

On charging the lead storage battery, the oxidation state of lead changes from $ x_{1} $ to $ y_{1} $ at the anode and from $ x_{2} $ to $ y_{2} $ at the cathode. The values of $ x_{1}, y_{1}, x_{2}, y_{2} $ are respectively:

Correct order of limiting molar conductivity for cations in water at $ 298 \, \text{K} $ is:

Based on the data given below:
$ E^\circ_{Cr_2O_7^{2-}/Cr^{3+}} = 1.33 \, \text{V} $ $ E^\circ_{Cl_2/Cl^-} = 1.36 \, \text{V} $
$ E^\circ_{MnO_4^-/Mn^{2+}} = 1.51 \, \text{V} $ $ E^\circ_{Cr^{3+}/Cr} = -0.74 \, \text{V} $
The strongest reducing agent is:

Given below are two statements:
$ 1 \,\text{M} $ aqueous solutions of each of $ \mathrm{Cu(NO_3)_2,\,AgNO_3,\,Hg_2(NO_3)_2,\,Mg(NO_3)_2} $ are electrolysed using inert electrodes.
$ \text{Given } E_{\text{Ag}^+/\text{Ag}}^\theta = 0.80\text{ V}, \, E_{\text{Hg}_2^{2+}/\text{Hg}}^\theta = 0.79\text{ V}, \, E_{\text{Cu}^{2+}/\text{Cu}}^\theta = 0.34\text{ V and } E_{\text{Mg}^{2+}/\text{Mg}}^\theta = -2.37\text{ V}$
Statement (I): With increasing voltage, the sequence of deposition of metals on the cathode will be Ag, Hg and Cu.
Statement (II): Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.
In the light of the above statements, choose the most appropriate answer from the options given below:

$ 1 $ Faraday electricity was passed through $ \mathrm{Cu}^{2+} $ $ (1.5 \, \mathrm{M}, \, 1 \, \mathrm{L}) $/Cu and $ 0.1 $ Faraday was passed through $ \mathrm{Ag}^{+} $ $ (0.2 \, \mathrm{M}, \, 1 \, \mathrm{L}) $/Ag electrolytic cells. After this the two cells were connected as shown below to make an electrochemical cell. The emf of the cell thus formed at $ 298 \, \mathrm{K} $ is ________ $ \mathrm{mV} $ (Nearest integer)

Given:
$ E^{\circ}_{\mathrm{Cu}^{2+}/\mathrm{Cu}} = 0.34 \, \mathrm{V} $
$ E^{\circ}_{\mathrm{Ag}^{+}/\mathrm{Ag}} = 0.8 \, \mathrm{V} $
$ \frac{2.303RT}{F} = 0.06 \, \mathrm{V} $

10.

$ 40 \, \text{mL} $ of a mixture of $ \mathrm{CH_3COOH} $ and $ \mathrm{HCl} $ (aqueous solution) is titrated against $ 0.1 \, \text{M} $ $ \mathrm{NaOH} $ solution conductometrically. Which of the following statement is correct?

11.

The molar conductance of an infinitely dilute solution of ammonium chloride was found to be $ 185 \, \mathrm{S \, cm^2 \, mol^{-1}} $ and the ionic conductance of hydroxyl and chloride ions are $ 170 $ and $ 70 \, \mathrm{S \, cm^2 \, mol^{-1}} $, respectively. If molar conductance of $ 0.02 \, \mathrm{M} $ solution of ammonium hydroxide is $ 85.5 \, \mathrm{S \, cm^2 \, mol^{-1}} $, its degree of dissociation is given by $ x \times 10^{-1} $. The value of $ x $ is __________. (Nearest integer)

12.

Which of the following electrolyte can be used to obtain $ \mathrm{H_2S_2O_8} $ by the process of electrolysis?

13.

The molar conductivity of a weak electrolyte when plotted against the square root of its concentration, which of the following is expected to be observed?

14.

The standard cell potential $ \left(E^\circ_{\text{cell}}\right) $ of a fuel cell based on the oxidation of methanol in air that has been used to power television relay station is measured as $ 1.21 \, \text{V} $. The standard half cell reduction potential for $ \mathrm{O_2} $ $ \left(E^\circ_{\mathrm{O_2/H_2O}}\right) $ is $ 1.229 \, \text{V} $.
Choose the correct statement:

15.

For the given cell $ \mathrm{Fe^{2+}_{(aq)} + Ag^{+}_{(aq)} \rightarrow Fe^{3+}_{(aq)} + Ag_{(s)}} $
The standard cell potential of the above reaction is:Given:

16.

Given below are two statements:
Statement I: Mohr’s salt is composed of only three types of ions–ferrous, ammonium and sulfate.
Statement II: If the molar conductance at infinite dilution for ferrous, ammonium and sulfate ions are $ x_{1}, x_{2} $ and $ x_{3} \, \text{S cm}^{2} \text{ mol}^{-1} $, respectively then the molar conductance for Mohr’s salt solution at infinite dilution would be given by $ x_{1}+x_{2}+2 x_{3} $
In the light of the given statements, choose the correct answer from the options given below:

17.

For a $\text{Mg} | \text{Mg}^{2+}(\text{aq}) || \text{Ag}^{+}(\text{aq}) | \text{Ag}$ the correct Nernst Equation is:

18.

Match List-I with List-II

List-I Applications	List-II Batteries/Cell
(A) Transistors	(I) Anode - Zn/Hg ; Cathode - HgO + C
(B) Hearing aids	(II) Hydrogen fuel cell
(C) Invertors	(III) Anode-Zn; Cathode-Carbon
(D) Apollo space ship	(IV) Anode-Pb; Cathode-Pb \| PbO₂

Choose the correct answer from the options given below:

19.

Consider the following electrochemical cell at standard condition.
$ \mathrm{Au(s)\,|\,QH_2,\,Q\,|\,NH_4X(0.01\,M)\,|\,Ag^+(1\,M)\,|\,Ag(s)} $ $ E_{\mathrm{cell}} = +0.4 \, \mathrm{V} $
The couple $ \mathrm{QH_2/Q} $ represents quinhydrone electrode, the half cell reaction is given below:

$ \left[\text{Given : } E^{\circ}_{\mathrm{Ag^+/Ag}} = +0.8 \, \mathrm{V} \text{ and } \dfrac{2.303RT}{F} = 0.06 \, \mathrm{V} \right] $
The $ \mathrm{p}K_b $ value of the ammonium halide salt $ (\mathrm{NH_4X}) $ used here is __________. (nearest integer)

20.

Consider the following half cell reaction $ \mathrm{Cr_2O_7^{2-}(aq)} + 6e^- + 14\mathrm{H^+(aq)} \rightarrow 2\mathrm{Cr^{3+}(aq)} + 7\mathrm{H_2O(\ell)} $. The reaction was conducted with the ratio of $ \dfrac{[\mathrm{Cr^{3+}}]^2}{[\mathrm{Cr_2O_7^{2-}}]} = 10^{-6} $. The pH value at which the EMF of the half cell will become zero is ______. (Nearest integer value)
[Given: standard half cell reduction potential $ E^\circ_{\mathrm{Cr_2O_7^{2-},\,H^+/Cr^{3+}}} = 1.33 \, \text{V} $, $ \dfrac{2.303\,RT}{F} = 0.059 \, \text{V} $]

21.

Electrolysis of $ 600 \, \mathrm{mL} $ aqueous solution of $ \mathrm{NaCl} $ for $ 5 \, \mathrm{min} $ changes the pH of the solution to $ 12 $. The current in Amperes used for the given electrolysis is ____________. (Nearest integer).

22.

Given below are two statements :
Statement (I) : Corrosion is an electrochemical phenomenon in which pure metal acts as an anode and impure metal as a cathode.
Statement (II) : The rate of corrosion is more in alkaline medium than in acidic medium.
In the light of the above statements, choose the correct answer from the options given below :

23.

Given below is the plot of the molar conductivity vs $ \sqrt{\text{concentration}} $ for $ \mathrm{KCl} $ in aqueous solution.

If, for the higher concentration of $ \mathrm{KCl} $ solution, the resistance of the conductivity cell is $ 100 \, \Omega $, then the resistance of the same cell with the dilute solution is ‘$ x $’ $ \Omega $. The value of $ x $ is ______. (Nearest integer)

24.

A solution of aluminium chloride is electrolysed for $ 30 $ minutes using a current of $ 2 \, \text{A} $. The amount of the aluminium deposited at the cathode is ________. [Given: molar mass of aluminium and chlorine are $ 27 \, \text{g mol}^{-1} $ and $ 35.5 \, \text{g mol}^{-1} $ respectively Faraday constant $ = 96500 \, \text{C mol}^{-1} $]

← PreviousQuestion 19 of 24Next →

JEE Main 2025 2nd April Morning Shift

JEE MainsJEE AdvanceBITSATJEE Mains | PYQ

JEE Mains JEE Advance BITSAT
JEE Mains | PYQ